Atlanta — The dramatic oil rig explosion and fire aboard the Transocean Deepwater Horizon rig 50 miles off the Louisiana coast illustrates the growing risk for oil companies as they drill ever deeper into the earth's crust to satisfy domestic and international demand for fuel.

As the US moves to open up more deep water areas for oil exploration and companies prepare to open up deep reserves off the coast of Brazil and Angola, the possible explosion and fire aboard the Deepwater Horizon rig, owned by Houston-based Transocean and leased by BP, is a reminder of how the task of supplying the world's oil amid dwindling reserves is becoming ever-more complex – and dangerous – despite technological advancements.

"Deep water drilling is already a high-stakes casino and as geologic risk, capital risk, market risk and engineering risk all come together, they are becoming extraordinarily difficult to quantify," says Robert Bryce, an energy expert at the Manhattan Institute and author of the upcoming book "Power Hungry: The myths of 'green' energy and the real fuels of the future."

The Deepwater Horizon is on the cusp of the world's oil exploration gambit.

Able to operate in up to 8,000 feet of water, it recently broke a world record in drill depth, punching 32,000 feet into the earth's crust. Complete with a bowling alley and movie theater, the Deepwater Horizon is also one of the largest and most advanced engineering projects on the planet – a fifth-generation exploration rig that had most recently been working BP's crude oil deposit in the Gulf of Mexico, called the Tiber.

"We're drilling deeper and deeper in Gulf of Mexico waters, Obama is about to lift the moratorium on part of the eastern Gulf, there's deep water Angola, so demand for this type of equipment continues to grow," says Jorge Pinon, former president of AmocoLatin America.

The Coast Guard said on Wednesday it has not found up to 12 crew members who were missing after the rig explosion Tuesday night, Reuters reported.

"Rigs are some of the safest places to be … which is what makes the explosion on the oil rig in the Gulf all the more unexpected and means it was likely one that happened very fast," reports CNN's Ali Velshi, who was once evacuated from an oil rig.

Most immediately, the Deepwater Horizon accident will affect BP, which was leasing the rig at the cost of about $450,000 a day, says Pinon. In 2005, BP's Thunder Horse deepwater rig in the Gulf nearly capsized from a plumbing error. Also in 2005, an explosion rocked BP's Texas City refinery, killing 15 and injuring scores of other workers. In 2006, one of BP's pipelines on Alaska's North Shore began leaking, forcing the company to re-lay 16 miles of pipe.

But while the Deepwater Horizon accident will give the industry pause, it's also a reminder, says Mr. Bryce, "that given all these risks, that all in all these kinds of catastrophic accidents are really pretty rare."